This invention relates to rotatable shelves, particularly for corner cabinets. The invention is an eccentric rotation and bearing system for a Reuleaux triangle type lazy susan especially useful in kitchen corner cabinets.
This invention is an improvement on Krayer U.S. Pat. No. 5,152,592, which discloses the use of a hypocycloid rotation guide for rotating a shelf in the shape of a Reuleaux triangle. FIGS. 5A to 5H of the ""592 patent illustrate that the rotation of a Reuleaux triangle-shaped shelf in a square area can be adapted to the standard area of a corner cabinet such as a corner kitchen cabinet in a generally square shape but having a 45xc2x0 face. During the rotation, the shelf contacts all four sides of the square area at all times. The kinematics of such a rotation permits various types of guides such as are shown in FIGS. 6-13 and 17-19 of the U.S. Pat. No. 5,152,592. The entire U.S. Pat. No. 5,152,592 is incorporated herein by reference.
While the shelf disclosed by Krayer in U.S. Pat. No. 5,152,592 is appealing in many respects, it has been criticized for its vulnerability to tipping if a significant downward force is applied to a projecting apex. Also, the ball casters installed on the underside of the shelf, as in FIG. 6C, were expensive and their longevity was suspect.
Accordingly, a different application of the hypocycloid principle is needed in the art of rotatable shelves.
The present invention utilizes planar bearings rather than ball caster bearings. The planar bearings permit the convenient use of an antitipping flange. In a preferred embodiment, rotation of the shelf is guided by the use of vertical axis rollers applied to the vertical side surfaces in a hypocycloid track or groove. In another embodiment, the bottom of the track or groove has a low-friction planar surface, and feet or nubs projecting from the shelf for sliding in the groove have complementary low friction planar surfaces.